In non-residential buildings, such buildings have various sizes dedicated to various uses such as for offices, retail and manufacturing. These buildings typically define relatively large open spaces within the interior thereof that are then outfitted with various interior structures. For office buildings, such interior structures may be space-dividing wall panels that subdivide the open office areas into smaller rooms or work stations. For retail spaces, the open interior building spaces may be outfitted or subdivided with various sales fixtures, equipment and display fixtures. Generally for non-residential buildings, the open interior spaces are outfitted with a configuration of lighting as well as an additional power supply system which provides receptacles in appropriate locations within the interior space, and with additional power supply connections for various pieces of equipment used within such spaces.
Large non-residential buildings typically are connected to an outside power source providing three-phase power wherein transformers reduce this higher voltage to selected lower voltages suitable for the electrical power distribution systems provided within the space. For example, ceiling lighting fixtures often use 277 volts or 347 volt circuits as their power supply to increase the number of fixtures on a single circuit, while most other items, such as wall-mounted receptacles, are powered by 120 volt service.
For this building wiring, THHN wire is used almost exclusively in non-residential buildings and is a nylon-jacketed wire type. This wire is installed within conventional conduits and metal enclosures and connected to various electrical devices to assemble the power distribution system to power lighting and other building equipment.
The conventional “hard wiring” installation method first involves installing various protective components for these wires in the form of floor/wall channels or steel tube conduit. After the passages are installed, the THHN wires are inserted into the passages by bundling the wires into groups with each wire being supplied from a separate spool, and then pulling the wiring bundles through the passages from one end to the other, after which the wires are cut from the spools. At the upstream terminal end of the system, the wires are usually connected with a main power supply such as the circuit breaker box that typically is located near the exterior power source for the building. The wire bundles may be terminated at selected locations, such as in receptacle or junction boxes, wherein the free wire ends along each wiring run typically are enclosed within the various wiring boxes and are often connected to some wiring device such as wall receptacles, switches, lighting fixtures or other fixtures/equipment. Most of the wire ends are individually connected to a system component, such as a receptacle, through manual hard wiring by an electrician.
Typically, each run of passages or conduits is sized for the number of fixtures and devices being connected thereto, and accommodates multiple circuits that are defined by the bundle of wires wherein typically three circuits are defined in a wire bundle. As such, the conduits and passages will often have five wires, one wire serving as a hot wire for each of three separate circuits for a total of three hot wires, one neutral or common return serving each of the three circuits, and one safety grounding wire, also serving the plurality of circuits. Some conduits may only have a single circuit extending therethrough comprising only three wires, namely one circuit or hot wire, a common return or neutral wire, and a ground wire. For conventional wall-mounted receptacles, the three-wire circuit may carry 120 volts. Lighting fixtures, however, are often installed on a single circuit of 277 volts or 347 volts wherein this higher voltage, single circuit can power a greater number of fixtures so as to reduce the total number of circuits being routed through a building structure.
As described above, the wiring practices for a non-residential building are currently labor-intensive wherein it is desirable to reduce the complexity of this wiring process. Attempts have been made to introduce power distribution systems comprising components wherein some of the system connections are already formed in the components in the manufacturing stage which therefore serves to transfer the labor from a job site and instead to a factory environment where automation and/or more efficient assembly processes can be applied in producing the system components. As a result of these efforts, some modular wiring systems and pre-bundled cables or conduits, namely MC cables, have been introduced and used which does reduce some of the on-site labor required to assemble the power distribution system.
In one example, pre-bundling or MC cable manufacturing involves automatic wrapping of a bundle of wires, usually three or five THHN wires, with a rolled metal strip that wraps circumferentially about the wire bundle and adjacent wraps interlock together along their edges to form a flexible metal jacket or flexible conduit. These MC cables are still formed in a long length wound onto large 1,000 foot spools, which spools are then shipped to local distributors and then cut to length as needed at the job site.
At the job site, these flexible cables hence are pulled directly from point to point through building cavities to define the various electrical circuits within such buildings. After pulling of the flexible, jacketed cables to selected locations, the cables are then cut near the spool to a desired length with the metal shield being stripped off from a portion of each opposite end of the cable length for subsequent connection to the desired electrical components being joined thereto, such as a lighting fixture, receptacle, switch or other equivalent component. In this regard, the individual wire ends are stripped and connected to the system components by hand in substantially the same manner as the conventional hard-wiring process described above. This alternate process provides for faster installation of the wiring bundles with more efficient routing directly between cable terminations, although the laying of the cables and the individual fastening of the cables to the system components is still labor-intensive.
In a further effort to improve the wiring process, modular wiring has evolved into categories of uses, namely manufactured cable systems with end connectors, and office furniture power systems which are used in space-dividing wall panels and other furniture components. These two systems have some similarities but are currently developed as separate systems for different applications within the same building environment.
As to manufactured cable systems, current manufacturers usually make two versions of such cable systems wherein one is provided for the powering and switching of lighting circuits and lighting fixtures, and another system is provided for powering receptacles. It is believed that these current systems are not compatible with each other wherein one system is provided to develop the lighting circuits and the other system is used to develop power supply receptacles throughout the interior building spaces. Further, the lighting systems are known to have three different types which are each factory keyed for one of the three common voltages mentioned above wherein voltage keying prevents interconnection of circuits and components of different voltages even when the plug style used in such systems is identical between the three system types.
More particularly, each of these manufactured cable systems includes several standard cable lengths having connector plugs at opposite ends thereof, and the systems further include pre-wired termination boxes for switch cable connections and Y connections. Wiring devices such as switches and receptacles are still connected by hand in standard wall boxes for these systems. Further, lighting fixtures are often provided with an extension cable designed for its appropriate voltage that attaches to the next fixture in a circuit in a daisy-chain configuration.
In addition to the manufactured cable system, office furniture power systems also are used to supply the individual power circuits within the space-dividing furniture used within an interior space. These office furniture power systems usually embody proprietary designs developed by major furniture system manufacturers and as such, these competing systems are not designed to be easily interconnected with each other. These power systems are more complex than manufactured cable systems in that the only hard wire connection typically is at the point where the system connection is made to the building wiring such as at the power panel. The other connections within the furniture components are simple modular plug connections.
These office furniture systems typically are only 120 volt systems and have multiple circuits, such as three or four circuits, running parallel through the entire chain or series of interconnected wiring modules. Where necessary receptacles are attached by simple plug attachment to the wiring modules wherein the receptacles also can have circuit selection switches that are manipulated before installation so that the receptacle can be connected to a selected one of the plurality of circuits defined in the wiring modules. Because of the need for reconfiguration of the office furniture systems over time, these office furniture power systems are highly desirable in that they can be disconnected and reconfigured in conformance with the repositioning of the office furniture components.
The above modular systems provide advantages over the most basic hard wiring process, but also do have disadvantages associated therewith which limits the scope of application within a single building structure.
In this regard, the manufactured cable systems described above have a lower installed cost than hard wiring and are easier to reconfigure, but typically are not stocked by local electrical supply distributors so that the manufactured cable systems must be designed during the building planning stage to ensure that nearly exact quantities of each electrical component are obtained. If the order amounts are inadequate, later reorders can take several weeks to obtain which may unacceptably delay building construction.
It is not practical for a distributor to stock even a full range of products for a single brand of such systems because of the different types of systems, i.e. lighting versus power receptacles, and the numerous parts required for each of the three different voltage versions.
Office power furniture systems are considered to be lower cost than those systems described above and are made in higher volumes due to their extensive use in the office furniture industry. However, such products also are proprietary products, or the result of proprietary development such that any single power distribution system typically is not open-sourced but instead is developed and manufactured by or for a specific manufacturer. Further, the various system designs do not typically anticipate usage of such power systems outside of a furniture or office environment such that the power systems typically are limited to 120 volt applications.
Based upon the foregoing, it is found to be desirable to develop a universal building power system that overcomes disadvantages associated with existing systems and is universally adaptable for use to not only supply power to lighting circuits and building wall receptacle circuits, but also to supply power to modular space-dividing office furniture and other office furniture components. In this regard, it is an object that such a system be capable of being stocked at local electrical supply distributors and serve virtually all applications, such as lighting, wall receptacles and switches, floor raceways and floor-mounted electrical components and also be routable into modular office furniture components and systems. Further, it is desirable that the single power distribution system also be capable for use in all three of the voltage levels and be able to be voltage keyed to restrict uses of the components to the selected voltage level once such has been selected during the installation phase.
Further, the inventive system should be plug-connected throughout, starting at the breaker box, through the building, and into the furniture system and finally be able to accommodate installation of all lighting fixtures, receptacles, switches and other fixtures/equipment with a minimum of hard wiring.
As to receptacles, it is desirable that such receptacles have the circuit selection feature and be able to be connected to both a wall outlet box and an office furniture wiring module and be pre-keyed for 120 volts only. As such, the 120 volt receptacles could be readily stocked locally at a distributor and be the same receptacle as those supplied by an individual furniture supplier which therefore provides multiple supply options.
The system also desirably will be interconnectable with an open-sourced furniture power system wherein the furniture system would be available to all furniture manufacturers as an alternative furniture power system that could be installed in the manufacturer's office furniture in place of the proprietary systems currently in use. The office furniture system of the invention includes compatible power distribution assemblies (PDA's) for direct mounting in the raceway of a wall panel, receptacles and flex-connectors for interconnecting serially-adjacent PDA's together.
The invention therefore relates to a universal power distribution system for routing electrical circuits within a building structure to comprehensively provide electrical power to the building in ceiling configurations, wall-mounted configurations, raised floor configurations and in office furniture configurations. The system components for all of these configurations have common plug connectors that are interengagable with each other so as to be readily usable in a wide variety of applications.
The system generally comprises power distribution assemblies (PDA's) adapted for mounting within the modular raceways of building components, variable lengths of flexible conduit units for long conduit runs which have connector plugs at the opposite end thereof, and then individual circuit components such as receptacles, switches, fixture adapters, and junction boxes.
The system of the invention would most cost-effectively be formed as a three-circuit, five-wire system for use with both the wall-mounted and floor-mounted building applications at 120 volts, and for the office furniture configurations at the same voltage level. The system components would have five wires wherein three of the wires would be dedicated as hot wires corresponding respectively to each of the three circuits, with fourth and fifth wires respectively serving as a common neutral and common ground for the three circuits. The various components, such as the receptacles, could also have circuit selectors thereon so that the receptacle could be selectively engaged with one of the three circuits. However, the wire wires could be used to define two circuits (two hots, two neutrals, one ground) or the system components also may include more or less wires, such as three wires to define a single circuit or four wires.
For the high-voltage lighting power applications, similar components could also be used, such as a flexible conduit unit which would have the same appearance and plug connectors as the five-wire components. However, these alternate system components could be formed as three-wire, single-circuit components which carry a single circuit therethrough yet are still engagable with a five-wire component when voltage keyed alike so that one of the three wires in the three-wire component would be engagable with a selected one of the three circuits carried by the five-wire components. The three-wire components could have circuit selectors in the plugs so that only one circuit is accessed by the circuit selector and the plug connector located at the upstream or tapping end of the conduit unit.
Where the three-wire, single circuit components carry higher voltages, the voltage keying feature on the plugs would be set to correspond to the high voltage level such that these components would only be connectable with components keyed alike for such voltage level. Preferably, the voltage keys may only be set once by an electrician during installation which would prevent later unauthorized mixing of circuit components dedicated for different voltage levels. Also, for components designed solely for 120 volt circuits such as the PDA's and flex connectors used for office furniture, the voltage keying may be fixed in its position.
Further, the flexible conduit units are also engagable with wall-mounted outlet boxes so as to supply power thereto wherein either a switch or receptacle could be plugged into the plug connector that is accessible through the box depending upon the plug connector entering the box and the compatibility of such connector with the compatibility of the connector on the switch or receptacle.
All of the components use a common plug construction comprising a slotted contact block for supporting electrical contacts, and flat electrical contact which reduces space requirements for the plugs. The contacts are formed essentially in a plane and are deformable in the plane so that two interconnected contacts are coplanar and define a low-profile contact. Hence, a stack of vertically spaced contacts in each plug only requires a minimal height, and is efficient to manufacture and assemble in a contact-receiving contact block.
As described further herein, the overall inventive system is readily adaptable to form virtually any conventional circuit configuration found within conventional hard-wired systems yet is formed simply through the routing of the cables through the building cavities and interconnection is accomplished merely by plugging components together rather than through labor-intensive manual wiring. Some manual wiring of components may still be desirable and is possible through the use of system components having a plug and a pigtail configuration of individual wires projecting freely from the plug which pigtail wires may then be hard wired to off-the-shelf wiring components.
The inventive system thereby relates to a comprehensive system of compatible components which are designed to satisfy virtually all of the requirements of the power systems currently in use for building wiring.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.